Unofficially, Onterio McCalebb believes his NFL Scouting Combine 40-yard dashes were 4.27 seconds and 4.21. Two weeks later at the Auburn pro day, it was 4.29.

Unofficially, Onterio McCalebb believes his NFL Scouting Combine 40-yard dashes were 4.27 seconds and 4.21. Two weeks later at the Auburn pro day, it was 4.29.

How fast?

"If I work on my start," he says, "I think I could bust that."

But quicker than that, in the time it took the Bengals to change the 'R' to a 'C', his career has suddenly veered from offense to defense.

After racking up the fourth-most all-purpose yards in Auburn history, he's now a cornerback instead of a running back that averaged 6.4 yards per more than 400 carries. That will happen when you're venturing undrafted into the NFL at 5-10 and weigh just 168 to 170 pounds, depending on what you read.

"It hurt on me. Over the three months I tried to prove to everybody that I could play the game and I love the game. I'm not a troubled kid," McCalebb says of not getting called on Draft Day. "It kind of hurt to my heart. Then again, when I got that call afterwards I was like, 'It's OK. As long as I get an opportunity and get a chance to work hard.' I'm going to do whatever I can to help this team get to the playoffs. Whatever they want me to do."

Cornerback? At some point the Bengals figure to roll out McCalebb as a receiver or even out of the backfield as they try to fit in his returner's speed while special teams coach Darrin Simmons takes him under his wing.

But right now the position says "CB." The last time McCalebb played it was in a limited role at Hargrave Military Academy in Chatham, Va., where he says Auburn sent him to prep for his college career. Before that, when he played in his hometown of Fort Meade, Fla., he was also placed sparingly on the other side of the ball.

"When necessary," McCalebb says. "We made the playoffs every year and whenever it got to crunch time, that's when I played it."

Mark Carrier, the Bengals secondary coach, knows he'll have to go overtime with McCalebb at the May 10-12 rookie minicamp. When the team meets the night of May 9, there won't be time to go over drills and technique. That will be reserved for Xs and Os.

"We'll have to spend some time with him on the side. Maybe before, but definitely after practice," Carrier says of the five workouts. "I tell my 17-year-old son, 'Not everybody was made to play backwards.' You have to be special to play with your back to the wall."

Carrier has been in the NFL for 20 years, 12 of them as a top 10 pick and eight as an assistant coach, and he can't remember anyone making a switch to a position where he wasn't at least exposed to it in college. But he's not saying that McCalebb can't pull it off.

"This kid played major college, so he's got something about him. He'll be willing to do whatever needs to be done and that's a big part of it," Carrier says. "He's got the one thing you can't teach. Speed kills."

All of this is nothing new to McCalebb. Not for the fourth-grader who was taken away from his drug-dependent mother, or the teen who saw his father jailed, or the college prospect who ended up living with the family of his best friend's cousin.

"I've had to start from the bottom all my life," McCalebb says. "I've bounced from house to house. I never had anything given to me. My whole life I've had to work for whatever I wanted. Like I say, I was just waiting for my name to be called and I'm ready to go in there and work."

Adam Heller, his Columbus, Ohio agent, has heard about it all before, too.

"Some people have told him they didn't think he'd amount to much, and look what he's already accomplished," Heller said.

When the call came, McCalebb says, the Bengals seemed to be a good fit. The Saints and Bills called too, but he felt Heller had a good feel for the Bengals.

Heller may have grown up in Bengals Country, south of Dayton, but what sold him was how the Bengals worked out McCalebb at Auburn's pro day and tried him not only at receiver as well as running back, but also on defense.

"Onterio is the kind of guy that can do so many different things for you," Heller says. "For a guy that's undrafted, that's going to be a big thing. The fact that a team invested the time to look at him in a couple of different spots is a good sign. I had kept in touch with (director of player personnel) Duke Tobin during the whole process and got the sense they were interested in using him some different ways and that's going to help him."

Both agent and team did their homework, staying in touch between the March 5 pro day and the April 27 post-draft phone call. The Bengals loved the speed, character and heart. Heller liked the fit and interest.

Another plus for Cincinnati is that McCalebb's old head coach at Hargrave, Robert Prunty, is the new University of Cincinnati associate head coach under Tommy Tuberville. It was during Tuberville's last season at Auburn in 2008 that the Tigers first expressed interest in McCalebb out of high school and new head coach Gene Chizik remained interested once McCalebb emerged from Hargrave.

"He taught me everything coming out of prep school," McCalebb says.

But Prunty couldn’t teach him speed. That's why he's here. It's why McCalebb is looking at Kansas City's Dexter McCluster. The 5-9, 165-pound McCluster is his NFL role model. McCluster may have been a high second-round pick in 2010, but McCalebb is the same size, maybe a tad bigger. In his three seasons, McCluster has 144 rushes, 119 catches, 51 kick returns and 17 punt returns.

McCalebb looks at the 5-8, 173-pound Tavon Austin, a burner who went in the top 10 of the draft and he thinks it's because playing wide receiver was a big help. McCalebb thinks he's got some skills receiving, too. He caught 63 balls in his career and only two top 20 rushers in Auburn history caught more in James Joseph and Mario Fannin. Not Bo Jackson, Joe Cribbs or four-time Bengals Pro Bowler James Brooks.

"I think I can play any position that's in my mind," McCalebb says. "No matter what it is, you're going to get 100 percent from me."